There's some difference, but my aluminum Shelby block could be made to work. I just didn't want to disassemble my engine and scavenge parts from it for a SOHC engine.
From Pond's website:
"Our SOHC Ford blocks are manufactured in both aluminum and cast iron. The specifics are the same as our wedge block, except they weigh 2 to 3 pounds more due to no lifter provisions and have a deck height of 10.170 instead of 10.155. Also, there are no oil passages in the lifter valley area. However, there is an oil return hole in the back of the block that is unique to the SOHC head."
SOHC Ford Block, RPM Racing